Accurate sighting and adjustment of the gun sights, especially telescopic sights, is especially critical for long-range sport and competitive shooting. In long range shooting, even very minor variations in gun or cartridge setup can make a significant difference in bullet location, so it is especially important for the equipment used to be stable and produce consistent results every time the gun is fired.
Good alignment of telescopic sight mounts is important, not only between front and rear mounts themselves, but between the mounts and the rifle bore of the firearm. Good alignment of the rifle bore is important so that the telescopic sight crosshairs will remain centered in the optics, necessary for good optical performance of the scope. Good alignment of the front and rear mounts is necessary to prevent undue mechanical stresses in the telescopic sight. Such stresses will affect the accuracy of the sight, and may result in damage to the optics or mechanical parts of the telescopic sight. Such stresses will also result in sight changes with time or when subjected to vibration or handling.
U.S. Pat. No. 5,813,131 discloses a pair of telescopic sight mount aligning bars. The bars have a circular end which reveals mount misalignment when clamped in the mount by non-parallelity between the inner ends. While this type of device is useful, it requires subjective evaluation to determine proper scope alignment. It is also relatively difficult and time consuming to mount and remount the bars after adjustments are made to recheck alignment. Also, the device lacks a “go/no-go” method to test whether alignment is sufficient.
There exists a for an alignment device for telescopic sight mounts which is quick and simple to use, and addresses shortcomings of previous devices.